Fuel metering system



July 1, 1958 A. J. zuPANclc 2,841,131

FUEL METERING SYSTEM Filed Feb. 21, 1957 2 Sheets-Sheet l ATTORNEY July1, 1958 A. J. ZUPANCIC 2,841,131

FUEL METERING SYSTEM Filed Feb. 21, 1957 2 Sheets-Sheet 2 IN V EN TOR. de'zf'fzaazzczi: BY

ATTORNEY United States Patent FUEL METERING SYSTEM 'Albert J. Zupancic,Royal Oak, Mich., assignor to General Motors Corporation, Detroit,Mich., a corporation of Delaware Application February 21, 1957, SerialNo. 641,629

Claims. (Cl. 123-119) The present invention relates to an improvedcontinuous flow type fuel metering system which is particularly adaptedfor use with a fuel induction system for an internal combustion engine.

The present system provides for the synchronized flow of fuel flow toall cylinders of the engine in sucha way as to insure an equalization ofthe power produced by each cylinder. Heretofore it has been the practicein most continuous flow fuel systems of the type to which the presentinvention relates to provide a single fuel metering valve forcontrolling the total quantity of fuel to be distributed to theindividual cylinders. To thus meter fuel with a single valve requiresrelatively large ports or passages which inherently are less accuratelycontrolled than small ports or passages. The present invention isdirected to providing a unique metering system in which individualmetering valves or their equivalents are utilized in supplying fuel tothe individual cylinders. In this way more accurate control of fuel fiowis realized with a resultant economy in fuel consumption as Well asbetter engine response to operator demand.

The present fuel metering system also includes a unique device wherebythe flow of fuel through the system is cut off under deceleratingconditions resulting in the reduction of the amount of unburnedhydrocarbons which are ungainfully exhausted from the engine. Thepresent inventionalso includes adevice adapted to operate ,inconjunction with the deceleration fuel cut-01f device for at leastperiodically reestablishing the flow of fuel during condi-,

tions of incipient stalling While the engine is being decelerated, andwhich device also permits the engine m idle properly with the throttlevalve closed.

Other improvements and advantages have resulted from the presentinvention as will be seen from a perusal of the detailed descriptionwhich follows.

In the drawings: y

Figure l is a diagrammatic representation of the fuel system embodyingthesubject invention;

Figure 2 is an isometric View of the fuel control valve; and

Figure 3 is a modification of the deceleration fuel cutoff system.

While the present fuel metering system has considerable generalapplicabilityv it is particularly adapted for use with a fuel inductionsystem of the type which has-been shown diagrammatically in Figure 1. InFigure l the fuel metering device is shown generally at A, an airinduc-' tion passage at B and a fuel supply pump at C. I

The metering device A includes a metering valve indicated generally at10 and a servo'device 12 adapted to actuate the valve in response tocertain engineoperating conditions as will now be more particularlydescribed. The servo device 12 includes a pair of easing members 14 and16 having a diaphragm member 18 peripherally clamped therebetween. has aspring supporting cavity 20 which houses one end of spring 22 the otherend of which coacts with the diaphragm 18 and urges the latter in adownwardly direction.

The upper casing member 14 2,841,131 Patented July 1, 1958 A disc orwasher-like member 24 is slidably disposed in casing portion 20 toprovide an adjustable seat for spring 22. Disc 24 may be axiallyadjusted by a screw 26 to vary the rate of the spring 22 and thus varythe operation of the diaphragm 18.

A boss 28 is also formed in theupper casing member 14 and within whichboss at fitting 30 is threadably mounted. Fitting 30 is adapted toconnect with a passage 32 the other end of which communicates with aventuri portion 34 of the induction passage B anteriorly of throttle 35.A vacuum signal or force is created in passage 32 which is directlyproportional to the mass of air flowing through the induction passage.This variable vacuum force is communicated to the chamber 36 defined bythe diaphragm 18 and the upper casing member 14 and works in oppositionto the spring 22 in controlling the movement of the diaphragm. As themass of air flowing through induction passage B increases the vacuumtransmitted to chamber 36 will similarly increase moving the diaphragmupwardly against the force of spring 22.

The diaphragm 18 has a rod 38 centrally fixed thereto which is adaptedto move up and down with the movement of the diaphragm. A lever 40 isarticulated intermediate its ends to the rod 38 and has one end 42 whichis pivotally connected to the fuel metering valve 10. The other end 44of lever 40 is appropriately articulated to a rod 46 to provide anadjustable fulcrum for the lever system 38-40.

The metering valve 10 shown in Figures 1 and 2 includes a plurality ofstepped or tapered portions 50. Valve 10 is slidably mounted within acasing 52. A flat spring element 54 is disposed between the casing 52and the sliding bar valve member 10 to retain the latter in positionwithin the casing. As better shown in Figure 2, casing. 52 has aplurality of longitudinally spaced ports 56 formed therein. An equalnumber of axially aligned ports 58 are disposed on opposite sides of thecasing. The sliding valve member 10 is adapted to slidably move betweenthe oppositely disposed sets of ports 56 and 58 such that each taperedvalve portion controls the flow of fuel to an oppositely disposed pairof ports 56 and 58. Casing 52 has a boss 60 formed therein which isadapted to have one end of a passage 62 connected thereto, the other endof the passage connecting with the fuel pump C which continuouslysupplies fuel under pressure to the casing 52. Each of the ports 56 and58 has a fuel line 64 connected thereto and each of which lines 64 isadapted to supply fuel for one cylinder of the engine.

An additional casing 68 is provided as a part of the fuel meteringdevice A and is contiguously disposed with respect to casing 52 having awall 70 in common therewith. Casings 52 and 68 are in communicationthrough an opening 72 in wall 70. An outlet 74 is formed in the bottomof casing 68 and communicates with any suitable passage means 76 leadingback to a fuel supply tank. The

- opening 72 is positioned that regardless of the position of thesliding bar valve 10 communication will at all times be establishedbetween the casings 52 and 68 providing a continuous flow of fuelthrough the fuel casing 52 to insure the fuel lines are at all timesfilled with fuel. Without providing for the continuous flow of fuelthrough the fuel metering system there would be a problem of air orvapor getting into the fuel lines resulting in an uneven flow of fuel ina line so affected.

In the species of fuel control valve shown in Figures 1 and 2 eachtapered or wedged shaped surface 50 of the valve 10 is'adapted to coactwith a pair of axially aligned ports to control the fuel flow thereto asdetermined by the valves position within the casing 52, as described inthe copending application Serial No. 633,349 filed January 9, 1957. Theposition of valve 10 is determined by the diaphragm member 18 which, asalready noted, is positioned in accordance with the mass of air flowingthrough induction passage B.

A pair of conduits 80 and 81 are connected in parallel with the passage32 in order to insure an adequate diaphragm controlled force underidling or low engine speed conditions. Conduit 80 communicates at oneend with the air induction passage immediately anterior of the throttle35 and at its other end with passage 32. Conduit 81 communicates at oneend With the induction passage immediately posterior to the throttle 35and likewise at its other end with passage 32. When the throttle isclosed no air will be flowing through the induction passage, therefore,there will be no vacuum from venturi 34 in passage 32. Under thiscondition manifold vacuum in the induction passage posteriorly of thethrottle 35 will be transmitted through conduit 81 to passage 32 andhence to chamber 36 whereby the diaphragm will be moved upwardly againstthe force of spring 22 to an extent which will cause the slide valve toat least partially uncover the ports 56 and 58 leading to the conduits64- feeding fuel to the individual cylinders, as described in Serial No.633,349. In order to prevent atmospheric air from being bled intopassage 32 and hence destroying the idle vacuum signal in conduits 81and 32, a restrictor or orifice 82 is formed in passage 32 which permitsthe maintenance of a sufiicient vacuum force in the metering chamber 36to insure the requisite flow of fuel for idling. An adjusting screw 84is provided in conduit 81 to permit adjustment of the quantity of idlingfuel.

Conduit 80 provides an elf-idle vacuum control force under conditionswhen the throttle is slightly opened and at which time the quantity ofair flowing through the induction passage is still too small to providean adequate control force in chamber 36. Under this condition the airflowing around throttle will create a vacuum in conduit which insures anadequate vacuum control force in chamber 36 until such time as the airbegins to flow in greater quantity through the venturi 34 to develop asuitable vacuum signal. An adjusting screw 85 is likewise provided inconduit 80 for adjusting the fuel flow under off-idle conditions.

An idle air passage 86 also communicates with the induction passageposteriorly of the throttle valve 35 and includes an adjusting screw 87whereby the idle air flowing into the induction passage may becontrolled thereby controlling the idling speed of the engine.

While the system as thus far described is sufficient to provide adequatefuel to the engine during idling and normal road load conditions, it isnecessary to provide a full load enrichment device, indicated generallyat 90, which will provide for additional fuel under high load or powerconditions. Device 90 includes a servo mechanism comprising upper andlower casing members 92 and 94 having a diaphragm 96 peripherallyclampedtherebetween and which diaphragm is urged downwardly by a springmember 98 disposed between the diaphragm 96 and the upper casing member92. The lower casing is suitably apertured to slidably mount the rod 46therein which is centrally fixed to the diaphragm 96. As already notedrod 46 has one end of lever 40 articulated thereto. The upper casing 92through a suitable connection 100 connects with any suitable passagecommunicating with the engine intake manifold whereby the chamber 102defined by the upper casing 92 and the diaphragm 96 has manifold vacuumcommunicated thereto. Manifold vacuum acts on the diaphragm 96 inopposition to the force of spring 98 to determine the position of rod46. Under normal operating conditions the manifold vacuum in chamber 102will be of a sufficiently high value to move the diaphragm to its upperposition, shown in Figure 1, to provide a road load .position for thefulcrum end 44 of .lever 40.

When the operator depresses the accelerator pedal, efiecting anincreased .power demand, manifold vacuum will decrease permitting thespring 98 to shift the rod 46 downwardly to its full load enrichmentposition and in so doing shift the sliding valve 10 upwardly tocompletely uncover the fuel ports 56 and 58 to provide the maximumamount of fuel to the cylinders. As soon as the maximum power situationhas been satisfied manifold vacuum will again increase shifting the rod46 once again to its upper or road load position for more economicaloperation. The upper casing member 92 has an adjustment screw 104.mounted therein for adjustably determining the road'load position of therod 46 which abuts thereagainst in its upward travel. Similarly anadjustment screw 106 is provided in casing 94 against which the lowerend of rod 46 is adapted to abut to determine the full load position ofthe rod. It is apparent that the adjustment screws 104 and 106 may beregulated in accordance with the type of engine operation desired. Whenthe rod 46 is shifted either under the influence of spring 98 ormanifold vacuum the point of connection of rod 40 and lever 38momentarily becomes the fulcrum point of the lever 40.

There are occasions in the operation of the engine when it is desirableto completely out off the supply of fuel to the fuel lines 64. Such anoccasion arises when the vehicle is decelerating under which conditionfuel normally continues to be supplied to the engine cylinders and atleast part of said fuel is pumped therefrom in an unburned state. As iswell known such a condition is both wasteful of fuel and contributes tothe contamination of the air.

To insure the cutting off of fuel to the engines cylinders when theengine is decelerating a valve mechanism indicated generally at 110 isprovided. Mechanism 110 includes a valve body 112 within which isslidably disposed a spindle type valve 114 having axially spaced lands116 and 118. A passage 32' leads from valve body 112 to the diaphragmcasing 14 and is in communication at all times with the space betweenlands 116 and 118. An atmospheric vent passage communicates with thevalve body 112 as does the vacuum passage 32. With the valve in theposition shown in Figure 1 land 116 blocks communication between vacuumpassage 32 and passage 32' while land 118 permits atmospheric passage120 to bleed atmospheric pressure to chamber 36 causing spring 22 toshift the diaphragm 18 and metering valve 10 to a position completelyclosing the fuel metering ports 5658. Spindle valve 114 is in theposition shown in Figure 1 only under engine decelerating conditions aswill now be described. Valve 114 is axially shifted by a solenoid 122which when energized, as shown in Figure 1, moves the valve to the rightagainst the force of a return spring 124. Solenoid 122 is adapted to beenergized by a switch 126 suitably mounted on the induction passagecasing. A lever 128 is connected with the throttle valve 35 in such away that when the throttle is closed lever 128 closes the contacts ofswitch 126 which conditions the circuit for energization of the solenoid122. However, in order for current to be supplied to the solenoid fromthe generator 130 the generator voltage output must be sufliciently high.to close a relay 132. The generator voltage will always be of asufiiciently high value during normal engine operating as well asdecelerating conditions to close the relay 132 and thus will alwaysenergize the solenoidlZZ when the throttle is closed. To insure pr peridling of the engine it is necessary that the spindle valve 114 beshifted to its normal running position in which land 116 uncovers vacuumpassage 32 permitting vacuum to act on diaphragm 18 for idling purposesas already described. Accordingly, relay 132 is so adjusted that thegenerator output under idling conditions is insufficient to maintain therelay in a closed position and 1hence, -notwithstanding that throttlevalve 35 has closed the switch '126, current cannot flow :to thesolenoid 122. Therefore, spring 124 will move the solenoid armature 134to the left causing land 116 to uncover passage 32 and at the same timecausing land 118 to block the atmospheric passage 120. In this way acontrol mechanism is provided whereby fuel is prevented from flowing tothe cylinders when the engine is decelerating but which mechanismpermits metered fuel to flow to the cylinders under idling conditions.

For the sake of convenience, relay 132 may be incorporated as a part ofthe voltage regulator by adding an additional set 'of relay pointsthereto and connecting switch 126 to one terminal thereof.

In lieu of the electrical deceleration fuel cut-ofi system shown inFigure 1 it is possible to utilize a mechanical system in which manifoldvacuum controls a valve 140. In this case valve 140 is controlled by aservo 142 which includes a diaphragm 144 to which the valve stem 146 iscentrally secured. A spring 148 within servo 142 normally biasesdiaphragm 144 to the right, as viewed in Figure 3, in which valve 140communicates passages 32 and 32'.

A casing 149 is suitably mounted on the induction passage casing andcommunicates with the passage posteriorly of'throttle 35 through aconduit 150. A valve element 152 is disposed within casing 149 andprojects through conduit 150in a manner permittingan enlarged headportion 154 to block flow through the conduit. A spring 156 normallybiases valve 152 to a position closing conduit 150. The other end 158 ofvalve 152 projects within the induction passage and is adapted to beengaged by an arm 160 fixed to throttle 35. When throttle 35 is closedarm 160 moves valve 152 to the open position admitting manifold vacuumto casing 149.

Another conduit 162 connects casing 149 with servo 142 admittingmanifold vacuum thereto when valve 152 is open. Thus with the throttleclosed and the engine decelerating the high manifold vacuum posterior tothrottle 35 will enter servo 142 and overcome spring 148 causing valve140 to block passage 32 and open passage 120 so as to bleed atmosphericpressure into metering chamber 36 causing fuel flow to be completely outofi as already described.

Since manifold vacuum under idling conditions is less than when theengine is decelerating spring 148 is cali brated to overcome idlingmanifold vacuum in servo 142 and shift valve 140 to the position shownin Figure 3 which permits the idling force to again control meteringdiaphragm 18.

The various embodiments of the invention as shown and described areillustrative and various structural modifications may be made within thescope of the invention as hereinafter set forth in the appended claims.

I claim:

1. A fuel metering system for an internal combustion engine comprisingan induction passage for delivering airto the cylinders of said engine,a throttle valve for controlling the quantity of air flowing throughsaid passage, a source of fuel under pressure, a plurality of fuelconduits each of which is adapted to deliver fuel to one cylinder ofsaid engine, valve means for metering the quantity of fuel delivered tosaid fuel conduits, first servo means connected to said metering valve,a venturi in the induction passage, a first conduit adapted tocommunicate the venturi with said servo means whereby said servo andmetering valve are responsive to the mass of air flowing through thesystem, a second conduit adapted to communicate atmospheric pressure tothe servo means, a valve device for controlling flow through saidconduits, a second servo for controlling said valve device, and throttlecontrolling means for actuating said second servo means whereby with thethrottle at least partially open said valve device will communicate thefirst conduit with said first servo means while with the throttle closedand the engine decelerating said valve device will communicate 6 thesecond conduit with the first servo means thereby cutting ofi the flowof fuel to the cylinders.

2. A fuel metering system for an internal combustion engine comprisingan induction passage for delivering air to the cylinders of said engine,a throttle valve for controlling the quantity of air flowing throughsaid passage, a source of fuel under pressure, a plurality of fuelconduits each of which is adapted to deliver fuel to one cylinder ofsaid engine, valve means for metering the quantity of fuel delivered tosaid fuel conduits, first servo means connected to said metering valve,a venturi in the induction passage, a first conduit adapted tocommunicate the venturi with said servo means whereby said servo andmetering valve are responsive to the mass of air flowing through thesystem, a second conduit adapted to communicate atmospheric pressure tothe servo means, a valve device for controlling flow through saidconduits, a second servo for controlling said valve device, throttlecontrolling means for actuating said second servo means whereby with thethrottle at least partially open said valve device will communicate thefirst conduit with said first servo means while the throttle closed andthe engine decelerating said valve device will communicate the secondconduit with the first servo means thereby cutting off the flow of fuelto the cylinders, and means responsive to engine speed for modifying theactuation of said second servo means by the throttle controlling means.

3. A fuel metering system as defined in claim 2 in which the enginespeed responsive means causes the second servo means to communicate thefirst conduit with the first servo whenever the engine is idling.

4. A fuel metering system for an internal combustion engine comprisingan induction passage for delivering air to the cylinders of said engine,a throttle valve for controlling the quantity of air flowing throughsaid passage, a source of fuel under pressure, a plurality of fuelconduits each of which is adapted to deliver fuel to one cylinder ofsaid engine, valve means for metering the quantity of fuel delivered tosaid fuel conduits, first servo means connected to said metering valve,a venturi in the induction passage, a first conduit adapted tocommunicate the venturi with said servo means whereby said servo andmetering valve are responsive to a vacuum force which is proportional tothe mass of air flowing through the system, a second conduit adapted tocommunicate atmospheric pressure to the servo means, a valve device forcontrolling flow through said conduits, a second servo for controllingsaid valve device, throttle controlling means for actuating said secondservo means whereby with the throttle at least partially open said valvedevice will communicate the first conduit with said first servo meanswhile with the throttle closed and the engine decelerating said valvedevice will communicate the second conduit with the first servo meansthereby cutting off the flow of fuel to the cylinders, and third conduitmeans communicating the induction passage proximate the throttle valvewith the first servo means whereby manifold vacuum will be deliveredtosaid latter servo means when the venturi vacuum force is insufficientto control the first servo means.

5. A fuel metering system as defined in claim 4 in which the thirdconduit means comprises a pair of passages connected in parallelrelation with the first conduit, one of said pair of passagescommunicating with the induction passage immediately anterior of thethrottle valve and the other of said passages similarly communicatingimmediately posterior of the throttle valve.

6. A fuel metering system for an internal combustion engine comprisingan induction passage for delivering air to the cylinders of said engine,a throttle valve for controlling the quantity of air flowing throughsaid passage, a source of fuel under pressure, a .plurality of fuelconduits each of which is adapted to deliver fuel to one cylinder ofsaid engine, valve means for metering the quantity of fuel delivered tosaid fuel conduits, first servo means con- I nected to said meteringvalve, a venturi in the induction passage, a first conduit adapted tocommunicate the venturi with said servo means whereby said servo andmetering valve are responsive to the mass of air flowing throughthesystem, a second conduit adapted to communicate atmospheric pressureto the servo means, a valve device for controlling flow through saidconduits, a solenoid for controlling said valve device, means normallybiasing said valve device in a position communicating said first conduitwith the first servo means, a switch for actuating said solenoid, saidthrottle being adapted when closed to close said switch to energize thesolenoid causing the valve device to communicate the second conduit withthe first servo'means whereby the metering valve cuts off the flow offuel to the cylinders, and engine speed responsive means fordeenergizing said solenoid when the engine reaches idling speed.

7. A fuel metering system as defined in claim 6 in which said enginespeed responsive means comprises an engine driven generator and a relayserially connected with said switch and said solenoid circuit, saidrelay being adapted to open said circuit when the engine reaches idlingspeed.

8. A fuel metering system for an internal combustion engine comprisingan induction passage for delivering air to the cylinders of said engine,a throttle valve for controlling the quantity of air flowing throughsaid passage, a source of fuel under pressure, a plurality of fuelconduits each of which is adapted to deliver fuel to one cylinder ofsaid engine, valve means for metering the quantity of fuel delivered tosaid fuel conduits, first servo means connected to said metering valve,a venturi in the induction passage, a first conduit communicating theventuri with said servo means whereby said servo and metering valve areresponsive to the mass of air flowing through the system, a secondconduit adapted to communicate atmospheric pressure to the servo means,a first valve device for controlling flow through said conduits, meansnormally biasing said valve to a position communicating the firstconduit with said first servo means, a second servo for controlling saidvalve device, a second valve device disposed in the induction passageposterior to the throttle valve, a third conduit connecting said secondvalve device with the second servo, and an element operable by thethrottle valve when closed to open the second valve device to permitmanifold vacuum to actuate the second servo means and therebycommunicate the second conduit with the first servo means to cut off theflow of fuel to the cylinders.

9. A fuel metering system as defined in claim 8 in which the valvebiasing means is calibrated to exceed the force of manifold vacuumacting on the second servo means under engine idling conditions whereasunder engine decelerating conditions the manifold vacuum force exceedsthat of the valve biasing means.

10. A fuel metering system as defined in claim 8 in which the secondvalve device includes spring means normally closing said device andthereby precluding manifold vacuum from entering said third conduit.

No references cited.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No,2,841,131 July .1, 1958 Albert J Zupanoic It is hereby certified thaterror appears in the printed specification of the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 5, line 47, after "idling" insert be vacuum Signed and sealedthis 7th day of October 1958.

SEAL) ttest:

KARL H-o .AXLINE Attesting Oflicer ROBERT C. WATSON Commissioner ofPatent;

